Practical Carriage Building
Compiled by M.T. Richardson, Vol.1. 1891
Swept Front Beds
As to why the front beds of some jobs are swept while others are made straight.
To go into a full explanation would require much time and space. I will try to get along without full detail, and think I will be understood. When called upon to construct a vehicle to order, make a sketch or rough drawing of the craft to be built. Next make all calculations as to height of wheels and springs, length of or track of axles; length, height, width, and cant of body, and make a scale drawing; and then, to assure yourself that you are right, put a full-sized drawing on the black board to see how it looks, and to again satisfy yourself that there are no errors. Next place the working drawing on the draft board, and go on with the work, satisfied that when completed there will be no faulty construction.
Having learned while making the draft that if you are to make a straight bed, the same as Fig. 206, in which A is the kingbolt and B B is where the body rests, that with a narrow front track the wheels would clear the cut under, but with a much wider track the wheels would strike the cut under E (Fig. 207), instead of at C, which would bring the front wheel in too close contact with the body. The bed could be moved well to the front of the boot B, and yet not clear, and would have to go even beyond and get under the bracket A.
To overcome that make a swept bed, as Fig. 208- A kingbolt, B B body rests—which, with the wide track, would bring the wheel at C, Fig. 207, center of cut under; while if you were to use the same bed with a narrow track, you would bring your wheels at D. As the width of the track is increased, so must the pivot or kingbolt be set ahead; and as the track is diminished, so is the pivot brought back by lessening the sweep in the front.—Iron Doctor.